1. Field of the Invention
The invention relates to respiratory devices.
2. Description of the Related Art
Positive Airway Pressure (PAP) devices that deliver a pressurized flow of breathable gas to a patient are known. Typically, these PAP devices include a pressure generator that pressurizes the breathable gas, and one or more sensors for monitoring various parameters of the breathable gas and/or the ambient atmosphere. A PAP device usually uses the information received from the sensor(s) to control the pressure generator in a feedback loop to provide the breathable gas to the patient at a desired pressure and/or flow. The PAP device may also monitor the total amount of gas provided to the patient.
In order to provide an enhanced accuracy in determining the pressure, flow, and/or total volume of the breathable gas delivered to the patient, some PAP devices include various mechanisms, such as a barometric pressure sensor to monitor atmospheric pressure, to improve accuracy of measurement. While these sensors may enhance the accuracy of the determination of the pressure, flow and/or total volume of the breathable gas, they add to the total cost of the device.